Fluctuations of Phytophthora and Pythium spp. in Components of a Recycling Irrigation System

Abstract

Stringent standards of water quality have prompted many horticultural enterprises to limit pollutant discharge associated with nutrient and pesticide applications. Collecting and recycling effluent is a method that has been implemented by many operations to contain pollutants; however, plant pathogens may be spread through recycled effluent. In this study, Phytophthora and Pythium spp. present in a water-recycling irrigation system at a perennial container nursery in southwestern Virginia were characterized using filtering and baiting techniques with two selective media. Members of Phytophthora were identified to species, whereas Pythium spp. were identified to genus only. Pythium spp. were recovered more frequently and in greater numbers than Phytophthora spp. Phytophthora capsici, P. citricola, P. citrophthora, P. cryptogea, P. drechsleri, and P. nicotianae were recovered in filtering assays. Only P. cryptogea and P. drechsleri were identified from baits placed on the surface of the irrigation reservoir, whereas P. cactorum, P. capsici, P. citricola, P. citrophthora, P. cryptogea, and P. drechsleri were recovered at depths, specifically at 1 and 1.5 m. This research provides data for development of detection technology and management practices for plant pathogens in irrigation water and may lead to improvements in conventional assay protocols.

Phytophthora hydropathica y Phytophthora drechsleri aisladas de canales de irrigación del Valle de Culiacán

“…found in irrigation water at different depths. For example, Bush et al (2003) found this species on the surface of irrigation water and at depths of 1 and 1.5 m. Two species of Phytophthora were isolated from the surface of 10 irrigation channels in the Culiacán Valley. In the channels where Phytophthora was found, P. hydropathical was found in only 40 %, in 30 % only P.drechsleri, and in 30 %, both species ( Figure 6).…”

“…El material vegetal fue lavado con agua corriente y desinfestado con etanol al 70 % durante 30 s antes de ser colocado en las trampas. Las trampas permanecieron en la superficie de los canales de riego durante 48 h (Bush et al, 2003). Posteriormente, las trampas se colectaron y se trasladaron al laboratorio.…”

“…Plant material was washed using tap water and disinfected with ethanol at 70 % for 30 s before being placed in the traps. The traps remained in the surface of the irrigation channels for 48 h (Bush et al, 2003). Afterwards, the traps were gathered and taken to the laboratory.…”

“…Las secuencias consenso mostraron una homología de 97 % con respecto a los aislamientos reportados en el NCBI para la especie Phytophthora drechsleri (GU111627 y AY659550) confirmándose así la identidad de estos aislamientos. P. drechsleri se ha encontrado en agua de irrigación a diferentes profundidades; por ejemplo, Bush et al (2003) encontró a esta especie en la superficie del agua de irrigación y a profundidades de 1 y de 1.5 m.…”

Plant stress activated by chlorine from disinfectants prepared on the base of sodium hypochlorite

“…Bush et al (2003) presented that recycled irrigation water from harbors contained substantial densities of pathogens and Hong and Moorman (2005) reported the presence of 17 Phytophthora sp., 26 Pythium sp., 27 genera of fungi, 8 species of bacteria, 10 viruses and 13 species of plant parasitic nematodes in irrigation water from ponds, rivers, canals, streams, lakes, runoff water, etc. These facts explain why chlorine is used for disinfection of irrigation water (Cayanan et al 2009).…”